A Concept for a Material That Softens With Frequency

Abstract

This work presents design concepts to synthesize composite materials with special dynamic properties, namely, materials that soften at high frequencies. Such dynamic properties are achieved through the use of a two-phase material that has inclusions of a viscoelastic material of negative elastic modulus in a typical matrix phase that has a positive elastic modulus. A possible realization of the negative-stiffness inclusion phase is presented. A numerical homogenization technique is used to compute the average viscoelastic properties of the composite. The method and the properties of a composite material designed with it are demonstrated through an example.